Current methods of cancer classification and diagnosis utilize mostly histological and morphological properties of the tumor, leading to generic and often unsuitable treatments for patients. Recent genomic advancements in oncology have established the ability to perform gene expression profiling of cancers, which can guide health workers towards a more patient-specific, accurate, and more successful treatment. The majority of cancer-based gene expression profiling is done using fluorescently labeled nucleic acid microarray technologies that are expensive, slow, and sometimes unreliable due to low sensitivity and specificity. Here, a completely new gene expression technology is proposed that, while obtaining high sensitivity and reliability, is designed to make gene expression profiling more accessible even to smaller clinical or hospital labs by utilizing a rapid and inexpensive system based on robust, electronic detection technology. The proposed gene expression profiling system will achieve these characteristics in a new type of microarray. This project will utilize two main thrusts to achieve these goals: 1) a new label-free, electrochemical-based hybridization sensor, and 2) confinement of each sensor using microactuators. The new sensor relies on an array of specific capture probes bound close to electrodes and surrounded by microactuators that assure confined analysis. The recognition of the right target is achieved by flow-through hybridization and an enzymatic cascade detection system enabling (i) linear amplification of the target above each sensor and (ii) transduction of this specific recognition into an electrical signal, which will be measured using a simple amperometric device similar to a glucometer. This new sensor will avoid the need for expensive nucleic acid labeling and optical/fluorescent detection equipment. The proposed device is well suited to micro-scale systems that can be operated as portable instruments at the bedside. The proposed microfluidic confinement of each sensor will eliminate sensor cross-talk and will increase sensitivity by confining enzyme products to small volumes. Objectives of this second thrust will be to obtain optimal fabrication and operation conditions to make an actuator of the desired size operate in the same conditions as the sensor. The overall goal of the Phase I and Phase II project is to validate the system and perform clinical testing of an integrated micro-scale gene expression profiling system for accurate genetics-based cancer diagnosis. In Phase I this system will be evaluated in terms of sensitivity and robustness using gene expression profiling based on several characteristic cancer genes by detecting small quantities of reconstituted cDNA or RNA from tumor cells. Clinical evaluations are envisioned to be performed in the Phase II project. [unreadable] [unreadable] [unreadable]